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U.S. Department of Energy
Office of Scientific and Technical Information

Evaluation of technology for large- and small-diameter boreholes to characterize crystalline rock

Technical Report ·
OSTI ID:5773998

Testing methods that have been used in large- and small-diameter boreholes (152 and 76 mm (6 and 3 in.)) were evaluated on their ability to characterize crystalline rocks. The methods evaluated included in-hole geomechanical, geophysical, and geohydrologic techniques and associated laboratory core tests; specific emphasis was on techniques that might be used in a field characterization program involving a small number of deep (up to 1500 m (5000 ft)) boreholes. Each technique was evaluated with regard to its effectiveness and limitations, applicability to the acquisition of data for anticipated rock conditions, and adequacy for assessing the required rock/hydrologic characteristics. Many pertinent case histories that helped to assess applicability were reviewed. A principal objective of the evaluations was to assess whether the techniques would be equally useful in both large- and small-diameter boreholes. Of the techniques evaluated, most are suitable for use in both large- and small-diameter boreholes. Borehole logging, hydrologic testing, and core-testing techniques provide suitable results in both borehole diameters. Geomechanical testing techniques provide suitable data in smaller diameter boreholes and have been designed for application at primarily shallow depths. The results of this study will be of use to the Office of Crystalline Repository Development (OCRD) in determining to what degree it is appropriate to use drilling, sampling, and testing techniques in small-diameter boreholes as opposed to large-diameter methods, while at the same time collecting adequate data for characterizing crystalline rock environments for potential use as a high-level radioactive waste repository. Additionally, further developmental work and specific testing techniques are recommended.

Research Organization:
Earth Technology Corp., Long Beach, CA (USA)
DOE Contract Number:
AC02-83CH10139
OSTI ID:
5773998
Report Number(s):
BMI/OCRD-21; ON: DE85012821
Country of Publication:
United States
Language:
English